5-Axis Milling Expertise for High-Tech Tool Making

14.03.2016

From left to right Gerhard Zech, machinery construction manger, Markus Gapp, milling group manager, both from Hirschmann Automotive GmbH, Florian König, sales manager for Austria/South Tyrol at Maschinenfabrik Berthold Hermle AG, and Andreas Bolter, tool and plant construction manager at Hirschmann Automotive GmbH, standing in front of the flagship C 52 U in the milling shop at the plant in Rankweil.

The roots of the current technology firm Hirschmann Automotive GmbH from Rankweil, A-6830 Austria, go back to Richard Hirschmann Electronic GmbH, which developed and produced telecommunication devices. The company first established a plant in Rankweil in 1959, and the building still serves as the headquarters of the international Hirschmann Automotive Group. The Group maintains seven production units in Austria, the Czech Republic, Romania (two factories), Morocco, China and, in the not too distant future, Mexico, at which 4,500 employees develop and produce numerous mechatronic products for the automotive sector across four product groups: overmoulded technology, connector systems, special cable assemblies and sensor systems. The level of diversification at the seven production units results from the fact that customers producing products on a global scale demand local sources of supply that guarantee the flexible JIT delivery of products and services, while expecting full technical support throughout the process, from design, through development to production. As mentioned above, the factory in Rankweil is the Group's head office, even though the individual production units are equipped and organised as centres of excellence for specific products and services. Management, administrative, development and manufacturing activities for connector systems, sensor systems, overmoulded technology and mechatronic subassemblies are concentrated in Rankweil. A further key role is played by the tool, machinery and plant construction departments, which employ 170 specialists in Rankweil alone. From the initial idea and development of products to the production of prototypes/samples, mould tools and the construction of assembly plants and robots: this is where all the elements of design, build and networking come together to implement the process chain all the way from basic drafts to commercialisation.

shows the working range of the high-performance, 5-axis CNC machining centre C 32 U with an NC rotary table for 5-axis/5-sided complete/simultaneous machining in one setup

Into the future with high-performance, 5-axis CNC machining centres

Gerhard Zech, machinery construction manager at Hirschmann Automotive GmbH explains the structure of his department: "Using relevant technologies, we develop ideal tool solutions that give guidance to the other production units, the majority of which have their own tool making departments. The tool making departments in the various countries enable the factories to respond quickly and flexibly to any problems and/or changes that may arise. The tool making branches are adequately equipped and basically responsible for carrying out maintenance, repairs and modifications." Living up to the company's motto: "Live the Innovation", Hirschmann Automotive GmbH has never been afraid to go its own way in many respects. A special mention must also go to the comparatively high number of trainees and the efficient way in which streamlining and investment plans are carried out after taking objective decisions. An excellent example of this is the refinement of the tool making machine portfolio in Rankweil. Andreas Bolter, tool and plant construction manager in Rankweil, comments: "Our work is governed by the efficiency of external tool manufacturers and we always have to be one step ahead. By focussing on the premium automotive sector and small to medium volumes of injection mould parts, we are able to offer a wide range of designs and tools. As we have to deliver just-in-time tool making services to the plant in Rankweil and the production unit in the Czech Republic, and soon in Mexico, problems in terms of machining capacity began to emerge. This was the incentive we needed to take a closer look at our machine portfolio for milling operations, especially as replacement purchases were necessary. There were a number of reasons why we selected Hermle as our partner of choice and started making extensive investments in 5-axis CNC machining centres. We had obtained very good results over a number of years with two Hermle C 20 U machining centres, one equipped with an IH 60 workpiece magazine and handling system, and were impressed with the provided performance and, in particular, the service. In contrast, other manufacturers had trouble meeting our expectations."

shows the working range of the high-performance, 5-axis CNC machining centre C 52 U with a 1,150 x 900 mm NC rotary table for large components weighing up to 2,000 kg

Five machining centres in one fell swoop for workpieces ranging from 5 x 5 x 10 mm to 1.5 tons

Actually, it was an unprecedented situation for Maschinenfabrik Berthold Hermle AG from Gosheim, D-78559: Hirschmann Automotive GmbH ordered a whole fleet (five for Rankweil and one for the Czech Republic) of cutting-edge, high-performance, 5-axis CNC machining centres of the Hermle C series, (C 12 U, C 22 U, C 32 U, C 42 U and C 52 U). They help to cover a wide range of capacities for individually machining items whose dimensions are just a few millimetres to large components and assemblies weighing up to 1.5 tons and measuring upwards of 500 x 1000 mm. Since the working ranges of the individual machine sizes overlap to a certain degree in the peripheral zones, milling capacities can be utilised in a highly flexible way for all machining tasks delivered on a direct application or prioritised basis. The tool making department was brought up to date in one fell swoop, thus experiencing enormous technology and productivity gains. At present, workers operate multiple machines on two shifts and unmanned production is carried out in a third shift. The 5-axis machining centres at the plant in Rankweil are currently still operated manually for one-offs and small-scale machining of tools and special machine components, the two larger machining centres, C 42 U and C 52 U, are however equipped with pallet changers or workpiece magazines for automated production. All the new machining centres feature more or less identical equipment and CNC technology, which is clearly advantageous in terms of training, programming, operating concepts and, last but not least, practical usage."

Effective synergies for greater acceptance and higher productivity

As a result, all the machines are equipped with the new TNC 640 Heidenhain control, NC rotary tables, HSK-A63 tool holding fixtures, main spindles with top speeds of 18000 rpm and, apart from the "smallest" 5-axis CNC machining centre (C 12 U), ACC function (Active Chatter Control) and AFC function (Adaptive Feed Control depending on the respective spindle output and other process parameters/data). Some of the machining centres are also fitted with additional magazines that, depending on the specific type and tool demands, enable complete machining of very complex workpieces in one setup. Once again the advantage of an overlapping effect between all the working ranges is very clear, since, depending on the size of the part and the machining requirements, the programmer and/or operator can choose the most suitable machine for the job, thus guaranteeing comprehensive capacity planning. For instance, mould inserts for injection mould tools with a high number of cavities are milled at the smaller machining centres, while the basic mould plates, etc. are produced in parallel at the larger machines, thus offering an effective and time-saving way to meet deadlines. The versatility, flexibility and multi-functionality provided by the Hermle machining centres offers many other benefits according to Gerhard Zech: "Roughly 2000 tool systems are in use worldwide. This means we have to overhaul about 120 tools a week. The similarity of the concepts and equipment of the Hermle machining centres and the daily experiences of employees have a highly positive impact on the working environment. Above all, training at the high-performance, 5-axis CNC machining centres, which is subsequently put into practice, is very relevant and practical, and staff have shown a high degree of acceptance from the start. We've discovered increased positive effects on identification and confidence among our highly-qualified operators in terms of the process components 'machine-tools-operator', which ultimately leads to maximum chip volume and higher productivity."